This invention relates generally to improved contact lens cleaning and conditioning solutions for removing and inhibiting build-up of tear film deposits and debris on lens surfaces.
In addition to the foregoing, the solutions of the present invention have improved versatility in being adaptable for most contact lens cleaning processes ranging from room temperature cleaning to high temperature disinfecting without adversely affecting the physical characteristics of the lenses.
When contact lenses are removed from the eyes, they lose water and retain on their surface a deposit or proteinaceous oily and sebaceous matter that, if not removed, greatly reduces wettability properties and optical clarity of the lenses. In the case of hard contact lenses fabricated from poly(methyl methacrylate), they are of such firmness the lenses can be treated with mechanical devices to remove deposits of contamination from their surfaces. Likewise, because hard contact lenses do not absorb appreciable amounts of water, the selection of cleaning agents is relatively non-critical. In many instances, use of even harsh disinfecting and cleaning agents on hard contact lenses does not create a problem.
However, because of the hydrophilic properties of soft contact lenses formulated from materials like poly(hydroxyethyl methacrylate), they do absorb more water than hard contact lenses. Consequently, greater care must be exercised in formulating cleansing solutions for soft contact lenses because materials in the solutions can be absorbed and concentrated in the lenses which in-turn can damage the lens and even injure the eyes of the user.
In many instances, solutions intended for hard contact lenses are generally not adaptable for use with soft contact lenses. This may be illustrated, for instance, in the case of hard contact lens solutions containing benzalkonium chloride or chlorobutanol, if used on soft contact lenses their important hydrophilic properties may be lost. Thus, in formulating contact lens care solutions, such as cleaning compositions, a number of factors need to be carefully weighed to assure total compatibility of the system in terms of functional efficaciousness, potential for damage to the lens and possible hazards to the wearer""s eyes.
Multipurpose solutions that clean and disinfect contact lenses have been described in the literature. For example, U.S. Pat. Nos. 4,820,352 to Riedhammer et al. and 5,096,607 to Mowrey-McKee et al. disclose such solutions. More generally, contact lens solutions are disclosed in U.S. Pat. Nos. 5,356,555 to Huth et al., 5,401,431 to Nakagawa et al., 5,409,546 to Nakagawa et al., 5,449,442 to Yamada et al., 5,487,788 to Kamiya et al., 5,505,953 to Chowhan, 5,556,480 to Rontome et al., 5,607,908 to Potini et al., 5,630,884 to Huth, 5,648,074 to Park et al., 5,654,262 to Desai et al., 5,800,807 to Huth et al., 5,820,696 to Kimura et al., 5,858,937 to Richard et al., 5,922,279 to Spooner, 6,024,954 to Park et al., and 6,121,327 to Tsuzuki et al.
Most multipurpose solutions require the user to apply the solution to the contact lens and then to rub the contact lens, either between two fingertips or between a fingertip and the palm of the other hand. This step is known as xe2x80x9cdigital rubbingxe2x80x9d, and enhances cleaning. If a multipurpose solution were effective to clean and disinfect contact lenses without rubbing, maintaining contact lenses would be simpler and easier. Thus it would be desirable to provide a safe and effective solution for cleaning contact lenses that does not require digital rubbing.
The invention provides a no-rub cleaning and disinfecting solution comprising an effective amount of an antimicrobial, a cleaning solution together with an effective amount of an osmolyte that increases osmolality of the total solution without adversely affecting the antimicrobial efficacy of the cleaning and disinfecting solution.
More specifically, the invention provides a solution comprising an effective amount of an antimicrobial together with from about 0.01 to about 15 weight percent of poly(oxypropylene)-poly(oxyethylene) adduct of ethylene diamine having a molecular weight from about 7500 to about 27,000 wherein at least 40 weight percent of said adduct is poly(oxyethylene), together with a tonicity adjusting agent in sufficient concentration to promote cleaning efficacy without adversely affecting antimicrobial efficacy. Solutions disclosed herein will contain preservatives to maintain product sterility. In addition, pH of the cleaning and conditioning solutions, for example, may be adjusted by the addition of isotonic saline and buffering agents.